Process for preparing short chain alkyl aromatic compounds

ABSTRACT

Relatively short chain alkyl aromatic compounds are prepared by alkylating an alkylatable aromatic compound with a relatively short chain alkylating agent under sufficient reaction conditions in the presence of a catalyst comprising zeolite MCM-56. The liquid phase syntheses of ethylbenzene and cumene are particular examples of such MCM-56 catalyzed reactions.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation-in-part of U.S. patent applicationSer. No. 08/051,952, filed Apr. 26, 1993, U.S. Pat. No. 5,362,697.

BACKGROUND

There is provided a process for preparing short chain alkyl aromaticcompounds by alkylating an aromatic compound with an alkylating agentemploying a particular synthetic porous crystalline material, designatedMCM-56, as a catalyst.

Zeolitic materials, both natural and synthetic, have been demonstratedin the past to have catalytic properties for various types ofhydrocarbon conversion. Certain zeolitic materials are ordered, porouscrystalline aluminosilicates having a definite crystalline structure asdetermined by X-ray diffraction, within which there are a large numberof smaller cavities which may be interconnected by a number of stillsmaller channels or pores. These cavities and pores are uniform in sizewithin a specific zeolitic material. Since the dimensions of these poresare such as to accept for adsorption molecules of certain dimensionswhile rejecting those of larger dimensions, these materials have come tobe known as "molecular sieves" and are utilized in a variety of ways totake advantage of these properties. Such molecular sieves, both naturaland synthetic, include a wide variety of positive ion-containingcrystalline silicates. These silicates can be described as a rigidthree-dimensional framework of SiO₄ and Periodic Table Group IIIAelement oxide, e.g., AlO₄, in which the tetrahedra are cross-linked bythe sharing of oxygen atoms whereby the ratio of the total Group IIIAelement, e.g., aluminum, and silicon atoms to oxygen atoms is 1:2. Theelectrovalence of the tetrahedra containing the Group IIIA element,e.g., aluminum, is balanced by the inclusion in the crystal of a cation,e.g., an alkali metal or an alkaline earth metal cation. This can beexpressed wherein the ratio of the Group IIA element, e.g., aluminum, tothe number of various cations, such as Ca/2, Sr/2, Na, K or Li, is equalto unity. One type of cation may be exchanged either entirely orpartially with another type of cation utilizing ion exchange techniquesin a conventional manner. By means of such cation exchange, it has beenpossible to vary the properties of a given silicate by suitableselection of the cation. The spaces between the tetrahedra are occupiedby molecules of water prior to dehydration.

Prior art techniques have resulted in the formation of a great varietyof synthetic zeolites. Many of these zeolites have come to be designatedby letter or other convenient symbols, as illustrated by zeolite Z (U.S.Pat. No. 2,882,243); zeolite X (U.S. Pat. No. 2,882,244); zeolite Y(U.S. Pat. No. 3,130,007); zeolite ZK-5 (U.S. Pat. No.3,247,195);zeolite ZK-4 (U.S. Pat. No. 3,314,752); zeolite ZSM-5 (U.S.Pat. No. 3,702,886); zeolite ZSM-11 (U.S. Pat. No. 3,709,979); zeoliteZSM-12 (U.S. Pat. No. 3,832,449); zeolite ZSM-20 (U.S. Pat. No.3,972,983); zeolite ZSM-35 (U.S. Pat. No. 4,016,245); and zeolite ZSM-23(U.S. Pat. No. 4,076,842), merely to name a few.

The SiO₂ /Al₂ O₃ ratio of a given zeolite is often variable. Forexample, zeolite X can be synthesized with SiO₂ /Al₂ O₃ ratios of from 2to 3; zeolite Y, from 3 to about 6. In some zeolites, the upper limit ofthe SiO₂ /Al₂ O₃ ratio is unbounded. ZSM-5 is one such example whereinthe SiO₂ /Al₂ O₃ ratio is at least 5 and up to the limits of presentanalytical measurement techniques. U.S. Pat. No. 3,941,871 (Re. 29,948)discloses a porous crystalline silicate made from a reaction mixturecontaining no deliberately added alumina in the recipe and exhibitingthe X-ray diffraction pattern characteristic of ZSM-5. U.S. Pat. Nos.4,061,724; 4,073,865; and 4,104,294 describe crystalline silicates ofvarying alumina and metal content.

U.S. Pat. No. 4,439,409 refers to a composition of matter named PSH-3and its synthesis from a reaction mixture containing hexamethyleneimine,an organic compound which acts as directing agent for synthesis of thepresently used MCM-56. A composition of matter appearing to be identicalto the PSH-3 of U.S. Pat. No. 4,439,409, but with additional structuralcomponents, is taught in European Patent Application 293,032.Hexamethyleneimine is also used for synthesis of MCM-22 in U.S. Pat. No.4,954,325; MCM-35 in U.S. Pat. No. 4,981,663; MCM-49 in U.S. Pat. No.5,236,575; and a ZSM-12 material in U.S. Pat. No. 5,021,141. Acomposition of matter referred to as zeolite SSZ-25 is taught in U.S.Pat. No. 4,826,667 and European Patent Application 231,860, said zeolitebeing synthesized from a reaction mixture containing an adamantanequaternary ammonium ion.

The alkylation of aromatic hydrocarbons with an olefin in the presenceof a zeolite having uniform pore openings of from about 6 to about 15Angstrom units is described in U.S. Pat. No. 2,904,607. U.S. Pat. No.3,251,897 describes the liquid phase alkylation of aromatic hydrocarbonsin the presence of X- or Y-type zeolites, specifically such zeoliteswherein the cation is a rare earth metal species and/or hydrogen. U.S.Pat. Nos. 3,751,504 and 3,751,506 describe the vapor phase alkylation ofaromatic hydrocarbons with olefins, e.g., benzene with ethylene, in thepresence of catalyst comprising, for example, ZSM-5.

U.S. Pat. Nos. 3,631,120 and 3,641,177, describe a liquid phase processfor the alkylation of aromatic hydrocarbons with olefins in the presenceof certain zeolites.

U.S. Pat. Nos. 4,962,256; 4,992,606; 4,954,663; 5,001,295; and5,043,501, each incorporated herein by reference in its entirety, teachalkylation of aromatic compounds with various alkylating agents overcatalyst comprising a particular crystalline material, such as PSH-3 orMCM-22. U.S. Pat. No. 4,962,256 describes preparing long chainalkylaromatic compounds by alkylating an aromatic compound with a longchain alkylating agent. U.S. Pat. No. 4,992,606 describes preparingshort chain alkylaromatics by alkylating an aromatic compound with ashort chain alkylating agent. U.S. Pat. No. 4,954,663 teaches alkylationof phenols, and U.S. Pat. No. 5,001,295 teaches alkylation ofnaphthalene. U.S. Pat. No. 5,043,501 describes preparation of2,6-dimethylnaphthalene.

U.S. Pat. Nos. 3,755,483 and 4,393,262 disclose the vapor phase reactionof propylene with benzene in the presence of zeolite ZSM-12, to productisopropylbenzene.

U.S. Pat. No. 4,469,908 discloses the alkylation of aromatichydrocarbons with relatively short chain alkylating agents having from 1to 5 carbon atoms employing ZSM-12 as alkylation catalyst.

Harper et al. have described a catalytic alkylation of benzene withpropylene over a crystalline zeolite (Petrochemical Preprints, AmericanChemical Society, vol. 22, no. 3, 1084 (1977)). Extensive kinetic andcatalyst aging studies were conducted with a rare earth exchanged Y-typezeolite (REY) catalyst.

Ethylbenzene is a valuable commodity chemical which is currently used ona large scale industrially for the production of styrene monomer.Ethylbenzene may be produced by a number of different chemical processesbut one process which has achieved a significant degree of commercialsuccess is the vapor phase alkylation of benzene with ethylene in thepresence of a solid, acidic ZSM-5 zeolite catalyst. In the production ofethylbenzene by this process, ethylene is used as the alkylating agentand is reacted with benzene in the presence of the catalyst attemperatures which vary between the critical temperature of benzene upto 900° F. (about 480° C.) at the reactor inlet. The reactor bedtemperature may be as much as 150° F. (about 85° C.) above the reactorinlet temperature and typical temperatures for the benzene/ethylenereaction vary from 600° to 900° F. (315° to 480° C.), but are usuallymaintained above about 700° F. (about 370° C.) in order to keep thecontent of the more highly alkylated benzenes such as diethylbenzene atan acceptably low level. Pressures typically vary from atmospheric to3000 psig (about 20785 kPa abs) with a molar ratio of benzene toethylene from about 1:1 to 25:1, usually about 5:1 (benzene:ethylene).Space velocity in the reaction is high, usually in the range of 1 to 6,typically 2 to 5, WHSV based on the ethylene flow, with the benzenespace velocity varying accordingly, in proportion to the ratio of thereactants. The products of the reaction include ethylbenzene which isobtained in increasing proportions as temperature increases togetherwith various polyethylbenzenes, principally diethylbenzene (DIEB) whichalso are produced in increasing amounts as reaction temperatureincreases. Under favorable operating conditions on the industrial scale,an ethylene conversion in excess of 99.8 weight percent may be obtainedat the start of the cycle.

In a commercial operation of this process, the polyalkylated benzenes,including both polymethylated and polyethylated benzenes are recycled tothe alkylation reactor in which the reaction between the benzene and theethylene takes place. By recycling the by-products to the alkylationreaction, increased conversion is obtained as the polyethylated benzenes(PEB) are converted to ethylbenzene (EB). In addition, the presence ofthe PEB during the alkylation reaction reduces formation of thesespecies through equilibration of the components because at a given feedcomposition and under specific operating conditions, the PEB recyclewill reach equilibrium at a certain level. This commercial process isknown as the Mobil/Badger process and is described in more detail in anarticle by Francis G. Dwyer, entitled "Mobil/Badger EthylbenzeneProcess-Chemistry and Catalytic Implications", appearing on pages 39-50of a book entitled Catalysis of Organic Reactions, William R. Moser,ed., Marcel Dekker, Inc. (1981).

Ethylbenzene production processes are described in U.S. Pat. Nos.3,751,504 (Keown); 4,547,605 (Kresge); and 4,016,218 (Haag); referenceis made to these patents for a detailed description of such processes.The process described in U.S. Pat. No. 3,751,504 is of particular notesince it includes a separate transalkylation step in the recycle loopwhich is effective for converting a significant proportion of the morehighly alkylated products to the desired ethylbenzene product. Otherprocesses for the production of ethylbenzene are disclosed in U.S. Pat.Nos. 4,169,111 (Wight) and 4,459,426 (Inwood), in both of which apreference for large pore size zeolites such as zeolite Y is expressed,in distinction to the intermediate pore size zeolites used in theprocesses described in the Keown, Kresge, and Haag patents. U.S. Pat.No. 3,755,483 (Burress) describes a process for the production ofethylbenzene using zeolite ZSM-12 as the alkylation catalyst.

Ethylbenzene (EB) can be synthesized from benzene and ethylene (C₂ ═)over a variety of zeolitic catalysts in either the liquid phase or inthe vapor phase. An advantage of a liquid phase process is its lowoperating temperature and the resulting low content of by-products.

U.S. Pat. No. 4,891,458 describes the liquid phase synthesis ofethylbenzene and cumene with zeolite beta.

U.S. Pat. No. 5,149,894 describes the liquid phase synthesis ofethylbenzene and cumene with a crystalline aluminosilicate materialdesignated SSZ-25.

Copending U.S. application Ser. No. 07/967,954, filed Oct. 27, 1992, nowU.S. Pat. No. 5,334,795, describes the liquid phase synthesis ofethylbenzene with a crystalline aluminosilicate material designatedMCM-22.

Copending U.S. application Ser. No. 08/078,369, filed Jun. 16, 1993, nowU.S. Pat. No. 5,371,390, describes the synthesis of short chainalkylaromatics with a crystalline aluminosilicate material designatedMCM-49.

SUMMARY

There is provided a process for preparing short chain alkyl aromaticcompounds, said process comprising contacting at least one alkylatablearomatic compound with at least one alkylating agent possessing analkylating aliphatic group having from 1 to 5 carbon atoms undersufficient reaction conditions and in the presence of a catalyst toprovide an alkylated aromatic product possessing at least one alkylgroup derived from said alkylating agent, said catalyst comprisingMCM-56, a synthetic porous crystalline material characterized by anX-ray diffraction pattern substantially as set forth hereinafter.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows the X-ray diffraction pattern of the dried product MCM-56of Example 1.

FIG. 2 shows the X-ray diffraction pattern of the calcined productMCM-56 of Example 2.

FIG. 3 shows the X-ray diffraction pattern of the dried product MCM-56of Example 9.

FIG. 4 shows the X-ray diffraction pattern of the calcined productMCM-56 of Example 10.

FIG. 5(a) shows the X-ray diffraction pattern of the Example 2 product.

FIG. 5(b) shows the X-ray diffraction pattern of the Example 3 product.

FIG. 5(c) shows the X-ray diffraction pattern of the Example 4 product.

FIG. 5(d) shows the X-ray diffraction pattern of the Example 5 product.

FIG. 6 is a graph showing a comparison of the activity of variouszeolite catalysts in the liquid phase synthesis of ethylbenzene.

FIG. 7 is a graph showing a comparison of the activity of variouszeolite catalysts in the liquid phase synthesis of cumene.

FIG. 8 is a graph showing propylene conversion as a function ofpropylene weight hourly space velocity for an MCM-56 catalyst in theliquid phase synthesis of cumene at various temperatures.

EMBODIMENTS

The entire contents of application Ser. No. 08/051,952 now, U.S. Pat.No. 5,362,697, filed Apr. 26, 1993, teaching MCM-56, are incorporatedherein by reference.

The term "aromatic" in reference to the alkylatable compounds which areuseful herein is to be understood in accordance with its art-recognizedscope which includes alkyl substituted and unsubstituted mono- andpolynuclear compounds. Compounds of an aromatic character which possessa hetero atom are also useful provided they do not act as catalystpoisons under the reaction conditions selected.

Substituted aromatic compounds which can be alkylated herein mustpossess at least one hydrogen atom directly bonded to the aromaticnucleus. The aromatic rings can be substituted with one or more alkyl,aryl, alkaryl, alkoxy, aryloxy, cycloalkyl, halide, and/or other groupswhich do not interfere with the alkylation reaction.

Suitable aromatic hydrocarbons include benzene, naphthalene, anthracene,naphthacene, perylene, coronene, and phenanthrene.

Generally the alkyl groups which can be present as substituents on thearomatic compound contain from 1 to about 22 carbon atoms and usuallyfrom about 1 to 8 carbon atoms, and most usually from about 1 to 4carbon atoms.

Suitable alkyl substituted aromatic compounds include toluene, xylene,isopropylbenzene, normal propylbenzene, alpha-methylnaphthalene,ethylbenzene, cumene, mesitylene, durene, p-cymene, butylbenzene,pseudocumene, o-diethylbenzene, m-diethylbenzene, p-diethylbenzene,isoamylbenzene, isohexylbenzene, pentaethylbenzene, pentamethylbenzene;1,2,3,4- tetraethylbenzene; 1,2,3,5-tetramethylbenzene;1,2,4-triethylbenzene; 1,2,3-trimethylbenzene, m-butyltoluene;p-butyltoluene; 3,5-diethyltoluene; o-ethyltoluene; p-ethyltoluene;m-propyltoluene; 4-ethyl-m-xylene; dimethylnaphthalenes;ethylnaphthalene; 2,3-dimethylanthracene; 9-ethylanthracene;2-methylanthracene; o-methylanthracene; 9,10-dimethylphenanthrene; and3-methyl-phenanthrene. Higher molecular weight alkylaromatichydrocarbons can also be used as starting materials and include aromatichydrocarbons such as are produced by the alkylation of aromatichydrocarbons with olefin oligomers. Such product are frequently referredto in the art as alkylate and include hexylbenzene, nonylbenzene,dodecylbenzene, pentadecylbenzene, hexyltoluene, nonyltoluene,dodecyltoluene, pentadecytoluene, etc. Very often alkylate is obtainedas a high boiling fraction in which the alkyl group attached to thearomatic nucleus varies in size from about C₆ to about C₁₂. When cumeneor ethylbenzene is the desired product, the present process producesacceptably little by-products such as xylenes. The xylenes make in suchinstances may be less than about 500 ppm.

Reformate containing substantial quantities of benzene, toluene and/orxylene constitutes a particularly useful feed for the alkylation processof this invention.

The alkylating agents which are useful in the process of this inventiongenerally include any aliphatic or aromatic organic compound having oneor more available alkylating aliphatic groups capable of reaction withthe alkylatable aromatic compound, the alkylating group possessing from1 to 5 carbon atoms. Examples of suitable alkylating agents are olefinssuch as ethylene, propylene, the butenes, and the pentenes; alcohols(inclusive of monoalcohols, dialcohols, trialcobols, etc.) such asmethanol, ethanol, the propanols, the butanols, and the pentanols;aldehydes such as formaldehyde, acetaldehyde, propionaldehyde,butyraldehyde, and n-valeraldehyde; and alkyl halides such as methylchloride, ethyl chloride, the propyl chlorides, the butyl chlorides, andthe pentyl chlorides, and so forth.

Mixtures of light olefins are especially useful as alkylating agents inthe alkylation process of this invention. Accordingly, mixtures ofethylene, propylene, butenes, and/or pentenes which are majorconstituents of a variety of refinery streams, e.g., fuel gas, gas plantoff-gas containing ethylene, propylene, etc., naphtha cracker off-gascontaining light olefins, refenery FCC propane/propylene streams, etc.,are useful alkylating agents herein. For example, a typical FCC lightolefin stream possesses the following composition:

    ______________________________________                                                      Wt. % Mole %                                                    ______________________________________                                        Ethane          3.3     5.1                                                   Ethylene        0.7     1.2                                                   Propane         14.5    15.3                                                  Propylene       42.5    46.8                                                  Isobutane       12.9    10.3                                                  n-Butane        3.3     2.6                                                   Butenes         22.1    18.32                                                 Pentanes        0.7     0.4                                                   ______________________________________                                    

Reaction products which may be obtained from the process of theinvention include ethylbenzene from the reaction of benzene withethylene, cumene from the reaction of benzene with propylene,ethyltoluene from the reaction of toluene with ethylene, cymenes fromthe reaction of toluene with propylene, and sec-butylbenzene from thereaction of benzene and n-butenes.

MCM-56 is a unique layered material having a composition involving themolar relationship:

    X.sub.2 O.sub.3 :(n)YO.sub.2,

wherein X is a trivalent element, such as aluminum, boron, iron and/orgallium, preferably aluminum; Y is a tetravalent element such as siliconand/or germanium, preferably silicon; and n is less than about 35, e.g.,from about 5 to less than about 25, usually from about 10 to less thanabout 20, more usually from about 13 to about 18. In the as-synthesizedform, the material has a formula, on an anhydrous basis and in terms ofmoles of oxides per n moles of YO₂, as follows:

    (0-2)M.sub.2 O:(1-2)R:X.sub.2 O.sub.3 :(n)YO.sub.2

wherein M is an alkali or alkaline earth metal, and R is an organicmoiety. The M and R components are associated with the material as aresult of their presence during synthesis, and are easily removed bypost-synthesis methods hereinafter more particularly described.

The MCM-56 material may be thermally treated and in the calcined formexhibits high surface area (greater than 300 m² /gm) and unusually largesorption capacity for certain large molecules when compared topreviously described materials such as calcined PSH-3, SSZ-25, MCM-22,and MCM-49. The MCM-56 wet cake, i.e., as-synthesized MCM-56, isswellable indicating the absence of interlayer bridges, in contrast withMCM-49 which is unswellable.

To the extent desired, the original alkali or alkaline earth, e.g.,sodium, cations of the as-synthesized material can be replaced inaccordance with techniques well known in the art, at least in part, byion exchange with other cations. Preferred replacing cations includemetal ions, hydrogen ions, hydrogen precursor, e.g., ammonium, ions andmixtures thereof. Particularly preferred cations are those which tailorthe catalytic activity for certain hydrocarbon conversion reactions.These include hydrogen, rare earth metals and metals of Groups IIA,IIIA, IVA, IB, IIB, IIIB, IVB and VIII of the Periodic Table of theElements.

The MCM-56 material appears to be essentially pure with little or nodetectable impurity crystal or layer phases and has an X-ray diffractionpattern which is distinguished by the combination of line positions andintensities from the patterns of other known as-synthesized or thermallytreated materials as shown below in Table I (as synthesized) and TableII (calcined). In these tables, intensities are defined relative to thed-spacing line at 12.4 Angstroms.

                  TABLE I                                                         ______________________________________                                                               Closest Relative                                                  Closest Relative                                                                          3-Dimensional                                                     Layered Material                                                                          Material MCM-49                                        MCM-56       Inter-            Inter-                                         Interplanar      planar          planar                                       d-Spacing                                                                             Relative d-Spac-  Relative                                                                             d-spacing                                                                            Relative                              (A)     Intensity                                                                              ing (A)  Intensity                                                                            (A)    Intensity                             ______________________________________                                        --      --       13.5     m      --     --                                    12.4 ± 0.2                                                                         vs       12.4     m-vs   12.5   vs                                    --      --       11.1     m      11.2   m-s                                   9.9 ± 0.3                                                                          m        --       --     --     --                                    --      --       9.2      m      9.0    m                                     6.9 ± 0.1                                                                          w        6.9      w      6.9    w                                     6.4 ± 0.3                                                                          w        6.7      w      6.4    w                                     6.2 ± 0.1                                                                          w        6.2      w      6.2    m                                     3.57 ± 0.07                                                                        m-s      3.56     w-m    3.55   w-m                                   3.44 ± 0.07                                                                        vs       3.43     s-vs   3.44   vs                                    ______________________________________                                    

                  TABLE II                                                        ______________________________________                                                   MCM-22      MCM-49                                                 MCM-56       Inter-            Inter-                                         Interplanar      planar          planar                                       d-Spacing                                                                             Relative d-Spac-  Relative                                                                             d-spacing                                                                            Relative                              (A)     Intensity                                                                              ing (A)  Intensity                                                                            (A)    Intensity                             ______________________________________                                        12.4 ± 0.2                                                                         vs       12.4     m-vs   12.4   vs                                    --      --       11.0     m-s    11.1   s                                     9.9 ± 0.3                                                                          m-s      --       --     --     --                                    --      --       8.8      m-vs   8.9    m-s                                   6.9 ± 0.1                                                                          w        6.9      w-m    6.9    w                                     6.2 ± 0.1                                                                          s        6.2      m-vs   6.2    m                                     3.55 ± 0.07                                                                        m-s      3.56     w-m    3.57   w                                     3.42 ± 0.07                                                                        vs       3.42     vs     3.43   s-vs                                  ______________________________________                                    

The materials used for generation of the data in Table I were wet cakelayered MCM-56, wet cake layered material synthesized with the sameorganic directing agent which, when calcined, transforms into MCM-22,and wet cake crystalline MCM-49. The materials used for the data inTable II were the calcined materials used for Table I. Calcination ofeach material was in air at 540° C. for 2-20 hours. The most effectivediagnostic feature allowing the initial differentiation between MCM-56and the other members of this family (MCM-22 and MCM-49-type materials)is observed in the region of 8.8-11.2 Angstroms d-spacing. The latterspecies exhibit two resolved maxima at approximately 8.8-9.2 Angstromsand 10.8-11.2 Angstroms with a distinct depression between them. MCM-56is characterized by a broad band centered around d-spacing 9.9Angstroms. While the band may have asymmetric profile, for example withan inflection point, the emergence of a depression may be indicative ofthe onset of MCM-49 formation and the loss of MCM-56.

These X-ray diffraction data were collected with a Scintag diffractionsystem, equipped with a germanium solid state detector, using copperK-alpha radiation. The diffraction data were recorded by step-scanningat 0.02 degrees of two-theta, where theta is the Bragg angle, and acounting time of 10 seconds for each step. The interplanar spacings,d's, were calculated in Angstrom units (A), and the relative intensitiesof the lines, I/I_(o) is one-hundredth of the intensity of the strongestline, above background, were derived with the use of a profile fittingroutine (or second derivative algorithm). The intensities areuncorrected for Lorentz and polarization effects. The relativeintensities are given in terms of the symbols vs=very strong (60-100),s=strong (40-60), m=medium (20-40) and w=weak (0-20). It should beunderstood that diffraction data listed for this sample as single linesmay consist of multiple overlapping lines which under certainconditions, such as differences in crystallographic changes, may appearas resolved or partially resolved lines. Typically, crystallographicchanges can include minor changes in unit cell parameters and/or achange in crystal symmetry, without a change in the structure. Theseminor effects, including changes in relative intensities, can also occuras a result of differences in cation content, framework composition,nature and degree of pore filling, and thermal and/or hydrothermalhistory. Other changes in diffraction patterns can be indicative ofimportant differences between materials, which is the case for comparingMCM-56 with similar materials, e.g., MCM-49, MCM-22, and PSH-3.

The significance of differences in the X-ray diffraction patterns ofthese materials can be explained from a knowledge of the structures ofthe materials. MCM-22 and PSH-3 are members of an unusual family ofmaterials because, upon calcination, there are changes in the X-raydiffraction pattern that can be explained by a significant change in oneaxial dimension. This is indicative of a profound change in the bondingwithin the materials and not a simple loss of the organic material. Theprecursor members of this family can be clearly distinguished by X-raydiffraction from the calcined members (e.g., compare middle columns ofTables I and II). An examination of the X-ray diffraction patterns ofboth precursor and calcined forms shows a number of reflections withvery similar position and intensity, while other peaks are different.Some of these differences are directly related to the changes in theaxial dimension and bonding.

Crystalline MCM-49 has an axial dimension similar to those of thecalcined members of the family and, hence, there are similarities intheir X-ray diffraction patterns. Nevertheless, the MCM-49 axialdimension is different from that observed in the calcined materials. Forexample, the changes in axial dimensions in MCM-22 can be determinedfrom the positions of peaks particularly sensitive to these changes. Twosuch peaks occur at ˜13.5 Angstroms and ˜6.75 Angstroms in precursorMCM-22, at ˜12.8 Angstroms and ˜6.4 Angstroms in as-synthesized MCM-49,and at ˜12.6 Angstroms and ˜6.30 Angstroms in the calcined MCM-22. The˜12.8 Angstroms peak in MCM-49 is very close to the intense ˜12.4Angstroms peak observed for all three materials, and is frequently notfully separated from it. Likewise, the ˜12.6 Angstroms peak of thecalcined MCM-22 material is usually only visible as a shoulder on theintense ˜12.4 Angstroms peak.

Other features which collectively distinguish MCM-56 from the similarmaterials described above are summarized in Table III below.

                  TABLE III                                                       ______________________________________                                        Feature       MCM-22    MCM-49      MCM-56                                    ______________________________________                                        As-synthesized:                                                               Structure     layered   3-dimensional                                                                             layered                                   Swellable     yes       no          yes                                       Condenses upon                                                                              yes       yes         no                                        Calcination                                                                   Calcined:                                                                     Sorption capacity                                                                           low       low         high                                      for 1,3,5-tri                                                                 methyl benzene.sup.1                                                          Initial uptake                                                                              slow      slow        fast                                      of 2,2-di-                                                                    methylbutane.sup.2                                                            ______________________________________                                    

When used as a catalyst, the layered MCM-56 material may be subjected totreatment to remove part or all of any organic constituent. Thecrystalline material can also be used as a catalyst in intimatecombination with a hydrogenating component such as tungsten, vanadium,molybdenum, rhenium, nickel, cobalt, chromium, manganese, or a noblemetal such as platinum or palladium where ahydrogenation-dehydrogenation function is to be performed. Suchcomponent can be in the composition by way of cocrystallization,exchanged into the composition to the extent a Group IIIA element, e.g.,aluminum, is in the structure, impregnated therein or intimatelyphysically admixed therewith. Such component can be impregnated in or onto it such as, for example, by, in the case of platinum, treating thesilicate with a solution containing a platinum metal- containing ion.Thus, suitable platinum compounds for this purpose includechloroplatinic acid, platinous chloride and various compounds containingthe platinum amine complex.

MCM-56 may be thermally treated without affecting its layered structurein that it is still swellable after thermal treatment. Thermal treatmentis generally performed by heating at a temperature of at least about370° C. for at least 1 minute and generally not longer than 20 hours.While subatmospheric pressure can be employed for the thermal treatment,atmospheric pressure is desired for reasons of convenience. The thermaltreatment can be performed at a temperature up to about 925° C. Thethermally treated product, especially in its metal, hydrogen andammonium forms, is particularly useful in the catalysis of certainorganic, e.g., hydrocarbon, conversion reactions. Non-limiting examplesof such reactions include those described in U.S. Pat. Nos. 4,954,325;4,973,784; 4,992,611; 4,956,514; 4,962,250; 4,982,033; 4,962,257;4,962,256; 4,992,606; 4,954,663; 4,992,615; 4,983,276; 4,982,040;4,962,239; 4,968,402; 5,000,839; 5,001,296; 4,986,894; 5,001,295;5,001,283; 5,012,033; 5,019,670; 5,019,665; 5,019,664; and 5,013,422,each incorporated herein by reference as to the description of saidcatalytic reactions.

The layered MCM-56 material, when employed either as an adsorbent or asa catalyst in an organic compound conversion process, should bedehydrated, at least partially. This can be done by heating to atemperature in the range of 200° C. to about 370° C. in an atmospheresuch as air, nitrogen, etc. and at atmospheric, subatmospheric orsuperatmospheric pressures for between 30 minutes and 48 hours.Dehydration can also be performed at room temperature merely by placingthe MCM-56 in a vacuum, but a longer time is required to obtain asufficient amount of dehydration.

The present layered MCM-56 material can be prepared from a reactionmixture containing sources of alkali or alkaline earth metal (M), e.g.,sodium or potassium, cation, an oxide of trivalent element X, e.g.,aluminum, an oxide of tetravalent element Y, e.g., silicon, directingagent (R), and water, said reaction mixture having a composition, interms of mole ratios of oxides, within the following ranges:

    ______________________________________                                        Reactants      Useful    Preferred                                            ______________________________________                                        YO.sub.2 /X.sub.2 O.sub.3                                                                     5 to 35  10 to 25                                             H.sub.2 O/YO.sub.2                                                                           10 to 70  16 to 40                                             OH.sup.- /YO.sub.2                                                                           0.05 to 0.5                                                                             0.06 to 0.3                                          M/YO.sub.2     0.05 to 3.0                                                                             0.06 to 1.0                                          R/YO.sub.2     0.1 to 1.0                                                                              0.3 to 0.5                                           ______________________________________                                    

In the present synthesis method, the source of YO₂ must be comprisedpredominately of solid YO₂, for example at least about 30 wt. % solidYO₂ in order to obtain the MCM-56 crystal product. Where YO₂ is silica,the use of a silica source containing at least about 30 wt. % solidsilica, e.g., Ultrasil (a precipitated, spray dried silica containingabout 90 wt. % silica) or HiSil (a precipitated hydrated SiO₂ containingabout 87 wt. % silica, about 6 wt. % free H₂ O and about 4.5 wt. % boundH₂ O of hydration and having a particle size of about 0.02 micron)favors crystalline MCM-56 formation from the above mixture under thesynthesis conditions required. Preferably, therefore, the YO₂, e.g.,silica, source contains at least about 30 wt. % solid YO₂, e.g., silica,and more preferably at least about 40 wt. % solid YO₂, e.g., silica.

Directing agent R is selected from the group consisting ofcycloalkylamine, azacycloalkane, diazacycloalkane, and mixtures thereof,alkyl comprising from 5 to 8 carbon atoms. Non-limiting examples of Rinclude cyclopentylamine, cyclohexylamine, cycloheptylamine,hexamethyleneimine, heptamethyleneimine, homopiperazine, andcombinations thereof.

Crystallization of the present layered material can be carried out ateither static or stirred conditions in a suitable reactor vessel, suchas for example, polypropylene jars or teflon lined or stainless steelautoclaves. The total useful range of temperatures for crystallizationis from about 80° C. to about 225° C. It is critical, however, forsynthesis of MCM-56 from the above reaction mixture to stop and quenchthe reaction prior to the onset of MCM-49 formation at the expense ofMCM-56. Thereafter, the MCM-56 is separated from the liquid andrecovered.

It should be realized that the reaction mixture components can besupplied by more than one source. The reaction mixture can be preparedeither batchwise or continuously.

MCM-56 can be shaped into a wide variety of particle sizes. Generallyspeaking, the particles can be in the form of a powder, a granule, or amolded product, such as an extrudate having particle size sufficient topass through a 2 mesh (Tyler) screen and be retained on a 400 mesh(Tyler) screen. In cases where the catalyst is molded, such as byextrusion, MCM-56 can be extruded before drying or partially dried andthen extruded.

Prior to its use in a catalytic process, the zeolite MCM-56 crystals maybe dehydrated, at least partially. This can be done by heating thecrystals to a temperature in the range of from about 200° C. to about595° C. in an atmosphere such as air, nitrogen, etc., and atatmospheric, subatmospheric or superatmospheric pressures for betweenabout 30 minutes to about 48 hours. Dehydration can also be performed atroom temperature merely by placing the crystalline material in a vacuum,but a longer time is required to obtain a sufficient amount ofdehydration.

It may be desired to incorporate the MCM-56 with another materialresistant to the temperatures and other conditions employed in organicconversion processes. Such materials include active and inactivematerials and synthetic or naturally occurring zeolites as well asinorganic materials such as clays, silica and/or metal oxides such asalumina. The latter may be either naturally occurring or in the form ofgelatinous precipitates or gels including mixtures of silica and metaloxides. Use of a material in conjunction with the new crystal, i.e.,combined therewith or present during synthesis of the new crystal, whichis active, tends to change the conversion and/or selectivity of thecatalyst in certain organic conversion processes. Inactive materialssuitably serve as diluents to control the amount of conversion in agiven process so that products can be obtained economically and orderlywithout employing other means for controlling the rate of reaction.These materials may be incorporated into naturally occurring clays,e.g., bentonite and kaolin, to improve the crush strength of thecatalyst under commercial operating conditions. Said materials, i.e.,clays, oxides, etc., function as binders for the catalyst. It isdesirable to provide a catalyst having good crush strength because incommercial use it is desirable to prevent the catalyst from breakingdown into powder-like materials. These clay and/or oxide binders havebeen employed normally only for the purpose of improving the crushstrength of the catalyst.

Naturally occurring clays which can be composited with the new crystalinclude the montmorillonite and kaolin family, which families includethe subbentonites, and the kaolins commonly known as Dixie, McNamee,Georgia and Florida clays or others in which the main mineralconstituent is halloysite, kaolinite, dickite, natrite, or anauxite.Such clays can be used in the raw state as originally mined or initiallysubjected to calcination, acid treatment or chemical modification.Binders useful for compositing with the present crystal also includeinorganic oxides, notably alumina.

The present catalyst may comprise MCM-56 and a matrix material such asalumina, silica, titania or a mixture thereof. In addition to theforegoing materials, MCM-56 can be composited with a porous matrixmaterial such as silica-alumina, silica-magnesia, silica-zirconia,silica-thoria, silica-beryllia, silica-titania as well as ternarycompositions such as silica-alumina-thoria, silica-alumina-zirconiasilica-alumina-magnesia, and silica-magnesia-zirconia.

The present catalyst may be in the form of extrudate, beads orfluidizable microspheres. The relative proportions of finely dividedcrystalline material and inorganic oxide matrix vary widely, with thecrystal content ranging from about 1 to about 90 percent by weight andmore usually, particularly when the composite is prepared in the form ofbeads, in the range of about 2 to about 80 weight percent of thecomposite.

Particularly when MCM-56 is bound by an extrusion process with analumina binder, the as-synthesized form of MCM-56 may be co-extrudedwith alumina to form a green strength extrudate. This green strengthextrudate may then be subjected to an ion exchange treatment withammonium ions prior to the initial calcination of the extrudate. Such abinding procedure, wherein ammonium exchange of a green strengthextrudate precedes the initial calcination of the extrudate, isdescribed in copending U.S. application Ser. No. 08/042,907, filed Apr.5, 1993, now U.S. Pat. No. 5,354,718. This procedure differs from thenormal procedure for preparing an alumina/zeolite extrudate, insofar asthe normal procedure involves calcination of the green strengthextrudate prior to the initial ammonium exchange of the extrudate.

The alkylation process of this invention is conducted such that theorganic reactants, i.e., the alkylatable aromatic compound and thealkylating agent, are brought into contact with the zeolite MCM-56catalyst composition in a suitable reaction zone such as, for example,in a flow reactor containing a fixed bed of the catalyst composition,under effective alkylation conditions. Such conditions include atemperature of from about 0° C. to about 500° C., and preferably betweenabout 50° C. and about 250° C. The reaction generally takes place atpressures of from about 0.2 to about 250 atmospheres and preferably fromabout 5 to about 100 atmospheres. The molar ratio of alkylatablearomatic compound to alkylating agent can be from about 0.1:1 to about50:1 and preferably can be from about 0.5:1 to about 10:1. Reaction issuitably accomplished utilizing a feed weight hourly space velocity(WHSV of between about 0.1 hr⁻¹ and about 500 hr⁻¹ and preferably from0.5 hr⁻¹ to about 100 hr⁻¹. The latter WHSV is based upon the totalweight of active catalyst (and binder if present).

The reactants can be in either the vapor phase or the liquid phase andcan be neat, i.e., free from intentional admixture or dilution withother material, or they can be brought into contact with the zeolitecatalyst composition with the aid of carrier gases or diluents such as,for example, hydrogen or nitrogen.

The alkylation process described herein can be carried out as abatch-type, semi-continuous or continuous operation utilizing a fixed ormoving bed catalyst system. A particular embodiment entails use of acatalyst zone wherein the hydrocarbon charge is passed concurrently orcountercurrently through a moving bed of particle-form catalyst. Thelatter, after use, is conducted to a regeneration zone where coke isburned from the catalyst in an oxygen-containing atmosphere (such asair) at elevated temperature, after which the regenerated catalyst isrecycled to the conversion zone for further contact with the organicreactants.

When benzene is alkylated with ethylene to produce ethylbenzene, thealkylation reaction may be carried out in the liquid phase. Suitableliquid phase conditions can be selected by reference to the phasediagram for benzene. In the liquid phase, the reaction is carried outwith the benzene feedstock in the liquid phase with the reactionconditions (temperature, pressure) appropriate to this end.

Liquid phase operation may be carried out at temperatures between 300°and 500° F. (about 150° to 260° C.), usually in the range of 400° to500° F. (about 205° to 260° C.).

Pressures during the liquid phase alkylation step may be as high asabout 3000 psig, (about 20875 kPa abs.) and generally will not exceed1000 psig (about 7000 kPa). The reaction may be carried out in theabsence of hydrogen and accordingly the prevailing pressures are thoseof the reactant species. In a high pressure liquid phase operation, thetemperature may be from about 300° to 600° F. with the pressure in therange of about 400 to 800 psig. The space velocity may be from about 0.1to 20 WHSV, based on the ethylene feed. Preferred space velocities forthe liquid phase reaction include ranges, for example, from about 0.5 toabout 3 WHSV, e.g., from about 0.75 to 2.0 WHSV, (ethylene). The ratioof the benzene to the ethylene in the alkylation reactor may be from 1:1to 30:1 molar, normally about 5:1 to 20:1 molar, and in most cases fromabout 5:1 to 10:1 molar.

When benzene is alkylated with propylene to produce cumene, the reactionmay also take place under liquid phase conditions including atemperature of up to about 250° C., e.g., up to about 150° C., e.g.,from about 10° C. to about 125° C.; a pressure of about 250 atmospheresor less, e.g., from about 1 to about 30 atmospheres; and an aromatichydrocarbon weight hourly space velocity (WHSV) of from about 5 hr⁻¹ toabout 250 hr⁻¹, from 5 hr⁻¹ to about 50 hr⁻¹. An example of acombination of reaction conditions includes a temperature of from about10° C. to 150° C, a pressure of from about 1 to about 30 atmospheres,and a WHSV of from about 5 to about 50 hr⁻. Another example of acombination of reaction conditions includes a temperature of from about10° C. to 250° C., a pressure of from about 1 to about 250 atmospheres,and a WHSV of from about 5 to about 250 hr⁻.

When conducting alkylation, various types of reactors can be used. Forexample, the process can be carried out in batchwise fashion by addingthe catalyst and aromatic feedstock to a stirred autoclave, heating toreaction temperature, and then slowly adding the olefinic feedstock. Aheat transfer fluid can be circulated through the jacket of theautoclave, or a condenser can be provided, to remove the heat ofreaction and maintain a constant temperature. Large scale industrialprocesses may employ a fixed-bed reactor operating in an upflow ordownflow mode or a moving-bed reactor operating with concurrent orcountercurrent catalyst and hydrocarbon flows. These reactors maycontain a single catalyst bed or multiple beds and may be equipped forthe interstage addition of olefins and interstage cooling. Interstageolefin addition and more nearly isothermal operation enhance productquality and catalyst life. A moving-bed reactor makes possible thecontinuous removal of spent catalyst for regeneration and replacement byfresh or regenerated catalysts.

In a particular embodiment of the present invention, the alkylationprocess is carried out with addition of olefin in at least two stages.Preferably, there will be two or more catalyst beds or reactors inseries, wherein at least a portion of the olefin is added between thecatalyst beds or reactors. Interstage cooling can be accomplished by theuse of a cooling coil or heat exchanger. Alternatively, interstagecooling can be effected by staged addition of the aromatic feedstock inat least two stages. In this instance, at least a portion of thearomatic feedstock is added between the catalyst beds or reactors, insimilar fashion to the staged addition of olefin described above. Thestaged addition of aromatic feedstock provides additional cooling tocompensate for the heat of reaction.

In a fixed-bed reactor or moving-bed reactor, alkylation is completed ina relatively short reaction zone following the introduction of olefin.Ten to thirty percent of the reacting aromatic molecules may bealkylated more than once. Transalkylation is a slower reaction whichoccurs both in the alkylation zone and in the remainder of the catalystbed. If transalkylation proceeds to equilibrium, better than 90 wt. %selectivity to monoalkylated product is generally achieved. Thus,transalkylation increases the yield of monoalkylated product by reactingthe polyalkylated products with additional benzene.

The alkylation reactor effluent contains the excess aromatic feed,monoalkylated product, polyalkylated products, and various impurities.The aromatic feed is recovered by distillation and recycled to thealkylation reactor. Usually a small bleed is taken from the recyclestream to eliminate unreactive impurities from the loop. The bottomsfrom the benzene distillation are further distilled to separatemonoalkylated product from polyalkylated products and other heavies. Inmost cases, the recovered monoalkylated product must be very pure. Inthe production of cumene, for example, impurities, such asn-propylbenzene, butylbenzenes, ethylbenzene and alpha- methylstyrene,all should be reduced to low (e.g., <100-300 ppm) levels since they areconverted during the oxidation process to make phenol from cumene. Onlysmall amounts of n-propylbenzene can be removed by distillation, and sothe catalyst should make very low levels of this impurity. It isimportant to have a feedstock which is relatively free of ethylene andbutylenes to avoid ethylbenzene and butylbenzenes in the cumene product;these contaminants can be removed by distillation, but to do so greatlyincreases the amount of required downstream fractionation.

Additional monoalkylated product may be produced by transalkylation. Thepolyalkylated products may be recycled to the alkylation reactor toundergo transalkylation or they may be reacted with additional aromaticfeed in a separate reactor. It may be preferred to blend the bottomsfrom the distillation of monoalkylated product with a stoichiometricexcess of the aromatic feed, and react the mixture in a separate reactorover a suitable transalkylation catalyst. The transalkylation catalystmay be a catalyst comprising a zeolite such as MCM-49, MCM-22, PSH-3,SSZ-25, zeolite X, zeolite Y, zeolite beta, or mordenite. Suchtransalkylation reactions over zeolite beta are disclosed in theaforementioned U.S. Pat. No. 4,891,458; and further suchtransalkylations using an acid dealuminized mordenite are disclosed inU.S. Pat. No. 5,243,116. Another particular form of mordenite, which maybe used as a transalkylation catalyst, is TEA mordenite, i.e., syntheticmordenite prepared from a reaction mixture comprising atetraethylammonium directing agent. TEA mordenite is disclosed in U.S.Pat. Nos. 3,766,093 and 3,894,104. The effluent from the transalkylationreactor is blended with alkylation reactor effluent and the combinedstream distilled. A bleed may be taken from the polyalkyated productstream to remove unreactive heavies from the loop or the polyalkyatedproduct stream may be distilled to remove heavies prior totransalkylation.

In order to more fully illustrate the nature of the invention and themanner of practicing same, the following examples are presented.

When Alpha Value is examined, it is noted that the Alpha Value is anapproximate indication of the catalytic cracking activity of thecatalyst compared to a standard catalyst and it gives the relative rateconstant (rate of normal hexane conversion per volume of catalyst perunit time). It is based on the activity of silica-alumina crackingcatalyst taken as an Alpha of 1 (Rate Constant=0.016 sec⁻¹). The AlphaTest is described in U.S. Pat. No. 3,354,078; in the Journal ofCatalysis, 4, 527 (1965); 6, 278 (1966); and 61, 395 (1980), eachincorporated herein by reference as to that description. Theexperimental conditions of the test used herein include a constanttemperature of 538° C. and a variable flow rate as described in detailin the Journal of Catalysis, 61, 395.

EXAMPLE 1

A mixture of 258 grams of water, 6 grams of 50% sodium hydroxidesolution, 13.4 grams of sodium aluminate solution (25.5% Al₂ O₃ and19.5% Na₂ O), 51.4 grams of Ultrasil (VN3), and 27.1 grams ofhexamethyleneimine (HMI) was reacted in a 600 ml stirred (400 rpm)autoclave at 143° C.

The reaction mixture had the following composition in mole ratios:

    ______________________________________                                               SiO.sub.2 /Al.sub.2 O.sub.3 =                                                          23                                                                   OH.sup.- /SiO.sub.2 =                                                                  0.21                                                                 Na/SiO.sub.2 =                                                                         0.21                                                                 HMI/SiO.sub.2 =                                                                        0.35                                                                 H.sub.2 O/SiO.sub.2 =                                                                  20                                                            ______________________________________                                    

The reaction was stopped at 34 hours. The product was filtered, washedwith water to form a wet cake, and a portion was dried in an oven at110° C.

A portion of the product wet cake and the dried portion were submittedfor X-ray analysis and identified as MCM-56. The X-ray diffractionpattern of the dried MCM-56 is presented below in Table IV and shown inFIG. 1.

                  TABLE IV                                                        ______________________________________                                        2 theta     d(A)    I/I.sub.o   Comments.sup.a                                ______________________________________                                        4.1         21.6    10          B                                             6.94        12.74   34          B, sh                                         7.15        12.36   100         S                                             8.9         9.9     32          VVB                                           12.84       6.89    12          B                                             13.89       6.38     7          VB, sh                                        14.32       6.18    15          S                                             15.92       5.57     8          VVB                                           19.94       4.45    30          VVB                                           21.98       4.04    43          B                                             22.51       3.95    59          VB                                            23.44       3.80    28          VVB                                           24.97       3.57    43          S                                             25.93       3.44    100         S                                             26.61       3.35    51          B                                             31.52       2.838    5          S                                             33.40       2.683   10          VVB                                           34.71       2.584    3          VVB                                           36.26       2.477    3          S                                             37.00       2.429    3          S                                             37.75       2.383    9          S                                             ______________________________________                                         .sup.a S = sharp, B = broad, VB = very broad, VBB = very very broad, sh =     shoulder                                                                 

The chemical composition of the product of Example 1 was, in wt. %,

    ______________________________________                                                N =    1.61                                                                   Na =   1.1                                                                    Al.sub.2 O.sub.3 =                                                                   6.6                                                                    SiO.sub.2 =                                                                          70.5                                                                   Ash =  78.2                                                           ______________________________________                                    

The SiO₂ /Al₂ O₃ molar ratio of this product was 18.

EXAMPLE 2

A portion of the product of Example 1 was ammonium exchanged bycontacting three times with 1M ammonium nitrate, and then calcined inair for 6 hours at 540° C. The X-ray diffraction pattern of the calcinedproduct of this example proved it to be MCM-56 and is presented below inTable V and shown in FIG. 2.

                  TABLE V                                                         ______________________________________                                        2 theta     d(A)    I/I.sub.o   Comments.sup.a                                ______________________________________                                        4.1         21.6    37          B                                             7.14        12.38   97          S                                             8.9         9.9     33          VVB                                           12.80       6.92    12          B                                             14.42       6.14    59          S                                             15.80       5.61    14          VVB                                           19.76       4.49    27          VVB                                           22.45       3.96    73          VVB                                           23.75       3.75    26          VVB                                           25.10       3.55    37          S                                             26.05       3.42    100         S                                             26.79       3.33    35          B                                             31.75       2.818    6          S                                             33.52       2.673   10          VVB                                           34.82       2.576    4          VVB                                           36.44       2.466    3          S                                             37.96       2.370    6          S                                             ______________________________________                                         .sup.a S = sharp, B = broad, VVB = very very broad                       

EXAMPLE 3

For comparison purposes, Example 1 of U.S. Pat. No. 4,954,325,incorporated herein by reference, was repeated. The as-synthesizedcrystalline material of the example, referred to herein as MCM-22precursor or the precursor form of MCM-22, was examined by X-raydiffraction analysis. Its X-ray diffraction pattern is presented inTable VI and shown in FIG. 5(b).

                  TABLE VI                                                        ______________________________________                                        2 theta         d(A)    I/I.sub.o                                             ______________________________________                                        3.1             28.5    14                                                    3.9             22.7    <1                                                    6.53            13.53   36                                                    7.14            12.38   100                                                   7.94            11.13   34                                                    9.67            9.15    20                                                    12.85           6.89     6                                                    13.26           6.68     4                                                    14.36           6.17     2                                                    14.70           6.03     5                                                    15.85           5.59     4                                                    19.00           4.67     2                                                    19.85           4.47    22                                                    21.56           4.12    10                                                    21.94           4.05    19                                                    22.53           3.95    21                                                    23.59           3.77    13                                                    24.98           3.56    20                                                    25.98           3.43    55                                                    26.56           3.36    23                                                    29.15           3.06     4                                                    31.58           2.833    3                                                    32.34           2.768    2                                                    33.48           2.676    5                                                    34.87           2.573    1                                                    36.34           2.472    2                                                    37.18           2.418    1                                                    37.82           2.379    5                                                    ______________________________________                                    

EXAMPLE 4

The product of Example 3 was calcined at 538° C. for 20 hours. The X-raydiffraction pattern of this calcined product is shown in Table VII belowand in FIG. 5(c).

                  TABLE VII                                                       ______________________________________                                        2 theta         d(A)    I/I.sub.o                                             ______________________________________                                        2.80            31.55   25                                                    4.02            21.98   10                                                    7.10            12.45   96                                                    7.95            11.12   47                                                    10.00           8.85    51                                                    12.90           6.86    11                                                    14.34           6.18    42                                                    14.72           6.02    15                                                    15.90           5.57    20                                                    17.81           4.98     5                                                    19.08           4.65     2                                                    20.20           4.40    20                                                    20.91           4.25     5                                                    21.59           4.12    20                                                    21.92           4.06    13                                                    22.67           3.92    30                                                    23.70           3.75    13                                                    25.01           3.56    20                                                    26.00           3.43    100                                                   26.96           3.31    14                                                    27.75           3.21    15                                                    28.52           3.13    10                                                    29.01           3.08     5                                                    29.71           3.01     5                                                    31.61           2.830    5                                                    32.21           2.779    5                                                    33.35           2.687    5                                                    34.61           2.592    5                                                    ______________________________________                                    

EXAMPLE 5

A 2.24 part quantity of 45% sodium aluminate was added to a solutioncontaining 1.0 part of 50% NaOH solution and 43.0 parts H₂ O in anautoclave. An 8.57 part quantity of Ultrasil precipitated silica wasadded with agitation, followed by 4.51 parts of HMI.

The reaction mixture had the following composition, in mole ratios:

    ______________________________________                                        SiO.sub.2 /Al.sub.2 O.sub.3 =                                                                 23                                                            OH.sup.- /SiO.sub.2 =                                                                         0.21                                                          Na/SiO.sub.2 =  0.21                                                          HMI/SiO.sub.2 = 0.35                                                          H.sub.2 O/SiO.sub.2 =                                                                         19.3                                                          ______________________________________                                    

The mixture was crystallized at 150° C. for 84 hours with stirring. Theproduct was identified as MCM-49 and had the X-ray pattern which appearsin Table VIII and FIG. 5(d).

The chemical composition of the product was, in wt. %,

    ______________________________________                                                N     1.70                                                                    Na    0.70                                                                    Al.sub.2 O.sub.3                                                                    7.3                                                                     SiO.sub.2                                                                           74.5                                                                    Ash   84.2                                                            ______________________________________                                    

The silica/alumina mole ratio of the product was 17.3.

The sorption capacities, after calcining at 538° C. for 9 hours were, inwt. %,

    ______________________________________                                        Cyclohexane, 40 Torr                                                                             10.0                                                       n-Hexane, 40 Torr  13.1                                                       H.sub.2 O, 12 Torr 15.4                                                       ______________________________________                                    

A portion of the sample was calcined in air for 3 hours at 538° C. Thismaterial exhibited the X-ray diffraction pattern shown in Table IX.

                  TABLE VIII                                                      ______________________________________                                        2 theta        d(A)    I/I.sub.o                                              ______________________________________                                        3.1            28.5    18                                                     3.9            22.8     7+                                                    6.81           12.99    .sup.  61 sh                                          7.04           12.55   97                                                     7.89           11.21   41                                                     9.80           9.03    40                                                     12.76          6.94    17                                                     13.42          6.60     4*                                                    13.92          6.36    17                                                     14.22          6.23    11                                                     14.63          6.05     2                                                     15.81          5.61    15                                                     17.71          5.01     4                                                     18.86          4.71     4                                                     19.23          4.62     6                                                     20.09          4.42    27                                                     20.93          4.24     8                                                     21.44          4.14    17                                                     21.74          4.09    37                                                     22.16          4.01    17                                                     22.56          3.94    58                                                     23.53          3.78    26                                                     24.83          3.59    22                                                     25.08          3.55    10                                                     25.86          3.45    100                                                    26.80          3.33    28                                                     27.53          3.24    21                                                     28.33          3.15    15                                                     28.98          3.08     4                                                     29.47          3.03     2                                                     31.46          2.843    4                                                     32.08          2.790    6                                                     33.19          2.699    9                                                     34.05          2.633    5                                                     34.77          2.580    4                                                     36.21          2.481    2                                                     36.90          2.436    3                                                     37.68          2.387    8                                                     ______________________________________                                         sh = Shoulder                                                                 + = Noncrystallographic MCM49 peak                                            * = Impurity peak                                                        

                  TABLE IX                                                        ______________________________________                                        2-Theta        d(A)    I/I.sub.o                                              ______________________________________                                        3.2            28.0     9+                                                    3.9            22.8     7+                                                    6.90           12.81    .sup.  48 sh                                          7.13           12.39   100                                                    7.98           11.08   46                                                     9.95           8.89    53                                                     12.87          6.88    10                                                     14.32          6.18    36                                                     14.74          6.01    11                                                     15.94          5.56    17                                                     17.87          4.96     2                                                     19.00          4.67     5                                                     19.35          4.59     3                                                     20.24          4.39    14                                                     21.06          4.22     5                                                     21.56          4.12    15                                                     21.87          4.06    25                                                     22.32          3.98    12                                                     22.69          3.92    41                                                     23.69          3.76    23                                                     24.95          3.57    19                                                     25.22          3.53     4                                                     25.99          3.43    90                                                     26.94          3.31    20                                                     27.73          3.22    17                                                     28.55          3.13    11                                                     29.11          3.07     3                                                     29.63          3.01     2                                                     31.59          2.833    6                                                     32.23          2.777    4                                                     33.34          2.687    9                                                     34.35          2.611    4                                                     34.92          2.570    3                                                     36.35          2.471    2                                                     37.07          2.425    2                                                     37.82          2.379    6                                                     ______________________________________                                         sh = Shoulder                                                                 + = Noncrystallographic MCM49 peak                                       

EXAMPLE 6

The product of Example 2 was subjected to the Alpha Test which indicatedan Alpha value of 106.

EXAMPLE 7

To compare microporosity and effective pore openings between MCM-56,MCM-22, and MCM-49, hydrocarbon compounds with increasing moleculardimensions were adsorbed sequentially onto portions of calcined MCM-56,MCM-22, and MCM-49 products of the examples according to the proceduredescribed by E. L. Wu, G. R. Landolt, and A. W. Chester in "NewDevelopments in Zeolite Science and Technology", Studies in SurfaceScience and Catalysis, 28, 547 (1986), incorporated herein by referenceas to this procedure. The dynamic sorption results of this investigationare presented in Table X below.

                  TABLE X                                                         ______________________________________                                                MCM-56        MCM-22        MCM-49                                    Sorbate   μl/g                                                                              sec.     μl/g                                                                            sec.   μl/g                                                                            sec.                               ______________________________________                                        n-Hexane  79     17       120   12    114   10                                2,2-Dimethyl-                                                                           60     12        72  252     85  233                                butane                                                                        1,3,5-Trimethyl-                                                                        41     24        8   550    undetectable                            benzene                                                                       ______________________________________                                    

The sorption results indicate clear distinction between the testedmaterials. MCM-56 has at least 4 times the capacity of MCM-22 and MCM-49for 1,3,5-trimethylbenzene, the most hindered hydrocarbon molecule usedin this investigation. MCM-56 also demonstrates a much faster initialrate of sorption of 2,2-dimethylbutane (time required to sorb the first15 mg of 2,2,-dimethylbutane/g of the sorbent at 80 Torr2,2-dimethyl-butane in flowing helium at 373° K.) than MCM-22 or MCM-49.The corresponding times for representative MCM-56, MCM-22, and MCM-49materials were 12, 252, and 233 seconds, respectively. The initial rateof sorption of n-hexane is the time required to sorb the first 40 mgn-hexane/g of sorbent and for 1,3,5-trimethyl- benzene, the timerequired to sorb the first 7 mg of 1,3,5-tri-methylbenzene/g of sorbent.

EXAMPLE 8

Example 1 was repeated, except that the reaction was stopped at 40hours. X-ray analysis proved the product to be MCM-56.

EXAMPLE 9

A mixture of 258 grams of water, 20.5 grams of sodium aluminate solution(25.5% Al₂ O₃ and 19.5% Na₂ O), 51.4 grams of Ultrasil (VN3), and 50grams of hexamethyleneimine (HMI) was reacted in a 600 ml stirred (400rpm) autoclave at 154° C.

The reaction mixture had the following composition in mole ratios:

    ______________________________________                                               SiO.sub.2 /Al.sub.2 O.sub.3 =                                                           15                                                                  OH.sup.- /SiO.sub.2 =                                                                   0.17                                                                Na/SiO.sub.2 =                                                                          0.17                                                                HMI/SiO.sub.2 =                                                                         0.66                                                                H.sub.2 O/SiO.sub.2 =                                                                   19                                                           ______________________________________                                    

The reaction was stopped at 130 hours. The product was filtered, washedwith water to form a wet cake, and a portion was dried in an oven for 2hours at 110° C.

A portion of the product wet cake and the dried portion were submittedfor X-ray analysis and identified as MCM-56. The X-ray diffractionpattern of the dried material is presented below in Table XI and shownin FIG. 3.

                  TABLE XI                                                        ______________________________________                                        2 theta     d(A)   I/I.sub.o    Comments.sup.a                                ______________________________________                                        4.1         21.6   30           B                                             6.67        13.25  23           B, sh.sup.b                                   6.96        12.70  24           B                                             7.16        12.35  80           S                                             8.9         9.9    21           VVB                                           12.86       6.88   14           B                                             13.98       6.33    7           VB, sh                                        14.33       6.18   15           S                                             15.85       5.59    7           VVB                                           19.93       4.45   25           VVB                                           21.95       4.05   42           VB                                            22.56       3.94   38           B                                             23.46       3.79   26           VVB                                           24.94       3.57   39           S                                             25.94       3.43   100          S                                             26.64       3.35   33           B                                             ______________________________________                                         .sup.a S = sharp, B = broad, VB = very broad, VVB = very very broad, sh =     shoulder                                                                      .sup.b Possible trace of MCM22 precursor                                 

The chemical composition of the product of Example 9 was, in wt. %,

    ______________________________________                                                N =    1.42                                                                   Na =   2.3                                                                    Al.sub.2 O.sub.3 =                                                                   9.3                                                                    SiO.sub.2 =                                                                          70.7                                                                   Ash =  82.3                                                           ______________________________________                                    

The SiO₂ /Al₂ O₃ molar ratio of this product was 13.

EXAMPLE 10

A portion of the dried sample from Example 9 was subjected to athree-fold exchange with a 1M ammonium nitrate solution. The solid wasthen heated in nitrogen at 482° C. for hours, cooled to about 130° C.,and then calcined in air at 538°C. for 5 hours. This material exhibitedthe X-ray diffraction pattern shown in Table XII and FIG. 4.

                  TABLE XII                                                       ______________________________________                                        2 theta     d(A)   I/I.sub.o    Comments.sup.a                                ______________________________________                                        4.3         20.5   69           B                                             7.13        12.40  100          S                                             8.1         10.9   33           VVB                                           9.8         9.0    37           VVB                                           12.79       6.92   12           B                                             14.38       6.16   48           S                                             15.78       5.62   17           VVB                                           19.74       4.50   24           VVB                                           22.45       3.96   69           VVB                                           23.70       3.75   23           VVB                                           25.10       3.55   36           S                                             26.05       3.42   88           S                                             26.86       3.32   27           B                                             31.71       2.822   5           S                                             33.34       2.687   9           B                                             34.30       2.614   6           VVB                                           36.40       2.468   5           S                                             37.92       2.373   5           S                                             ______________________________________                                         .sup.a S = sharp, B = broad, VVB = very very broad                       

The X-ray diffraction patterns of the product materials from Examples2-5 are presented in FIG. 5. FIG. 5(a) shows the pattern of the MCM-56product from Example 2; FIG. 5(b), the pattern of the product fromExample 3. The pattern of the MCM-22 product from Example 4 is shown inFIG. 5(c), and the pattern shown in FIG. 5(d) is from the MCM-49 productof Example 5. These patterns are presented in this Figure in a manner bywhich comparison is facilitated. FIGS. 5(b) and (c) are from theas-synthesized layered material which transforms into crystalline MCM-22upon calcination, and the crystalline MCM-22, respectively.

EXAMPLE 11

This Example describes the preparation of an MCM-56/alumina extrudate(1/16" diameter) comprising 65 wt. % MCM-56 and 35 wt. % alumina. 65parts by weight of as-synthesized MCM-56, having a silica to aluminamolar ratio of 18, and 35 parts by weight alumina (La Roche Versal 250)were mulled and extruded to form a 1/16" diameter extrudate. Thisextrudate was dried at 250° F. (121° C.). The dried extrudate wasexchanged with an aqueous solution of NH₄ NO₃ (10 ml solution/gramcatalyst). The exchanged extrudate was rinsed with deionized water. Therinsed extrudate was first dried at 250° F. (121° C.), followed bycalcination in nitrogen for 3 hours at 1000° F. (538° C.), and thencalcined in air for 8 hours at 1000° F. (538° C.).

EXAMPLE 12

This Example describes the use of the MCM-56/alumina extrudate catalystof Example 11 in the liquid phase synthesis of ethylbenzene (EB) frombenzene and ethylene (C₂ ═). The experiments were conducted with adownflow, three-zone isothermal fixed-bed unit. One gram of thiscatalyst (1/16" length, 1/16" diameter) was diluted to 10 cc with 20-60mesh quartz chips to make up the active bed. The reactor was operated at200°-320° C., 500 psig, 5.5 benzene/C₂ ═molar ratio, and 1.1-2.8 C₂═WHSV. Ethylene conversion was determined by measuring unreacted C₂═offgas relative to feed C₂ ═. Offgases were analyzed on a Carlerefinery gas analyzer and liquid products were analyzed on a Varian 3700GC. Total material balances were 100±2%. The performance of MCM-56 forliquid phase EB synthesis is compared with MCM-22, MCM-49, and zeolitebeta in FIG. 6 and Table XIII.

                  TABLE XIII                                                      ______________________________________                                        Ethylene Synthesis-Selectivity Comparison                                     Catalyst/     Zeolite                                                         35% Al.sub.2 O.sub.3                                                                        beta    MCM-22   MCM-49 MCM-56                                  ______________________________________                                        C.sub.2 ═ WHSV                                                                          2.2     1.1      1.1    1.1                                     Product dist., mol. %                                                         EB            88.0    94.0     95.3   93.4                                    DEB           10.6    5.7      4.5    6.2                                     TEB+          1.1     0.2      0.1    0.3                                     Σ       99.7    99.9     99.9   99.9                                    xylenes       0.00    0.00     0.00   0.00                                    n-C.sub.3 -Bz +                                                                             0.00    0.00     0.00   0.00                                    cumene                                                                        sec-C.sub.4 -Bz                                                                             0.13    0.07     0.06   0.04                                    other C.sub.9 +                                                                             0.14    0.02     0.02   0.05                                    aromatics                                                                     Σ (by-products)                                                                       0.27    0.09     0.09   0.09                                    ______________________________________                                         97.sup.+ % C.sub.2 ═ conversion at 220° C., 500 psig, and 5.5      benzene/C.sub.2 ═ molar ratio.                                       

FIG. 6 indicates that the relative catalyst activity at constant C₂═conversion is MCM-22: MCM-49: MCM-56: zeolite beta=1.0: 1.2: 1.6: 2.2.

Table XIII indicates that at 97⁺ % C₂ ═conversion, MCM-56's overallalkylation selectivity to EB and polyethylbenzene (99.9 mol %) iscomparable to zeolite beta, MCM-22, and MCM-49. MCM-56's EB selectivity(93 mol %) is comparable to MCM-22 and MCM-49, but 5 mol % higher thanzeolite beta (the most active catalyst tested). No deactivation wasobserved with MCM-56 during the two-week evaluation. Air regenerationdid not affect MCM-56 activity. These results indicate that MCM-56 ismore active than the MCM-22/-49 catalysts and more selective thanzeolite beta for liquid phase EB synthesis. The combination of highactivity and selectivity render MCM-56 a desirable liquid phasealkylation catalyst for EB.

EXAMPLE 13

This Example describes the use of the MCM-56/alumina extrudate catalystof Example 11 in the liquid phase synthesis of cumene from benzene andpropylene (C₃ ═). The experiments were conducted with a downflow,three-zone isothermal fixed-bed unit. One gram of this catalyst (1/16"length, 1/16 diameter) was diluted to 10 cc with 20-60 mesh quartz chipsto make up the active bed. The reactor was operated at 300 psig, 3benzene/C₃ ═molar ratio, 2.5-30 C₃ ═WHSV, and 50°-150° C. Propyleneconversion was determined by measuring unreacted C₃ ═offgas relative tofeed C₃ ═. Offgases were analyzed on a Carle refinery gas analyzer andliquid products were analyzed on a Varian 3700 GC. Total materialbalances were 100±2%.

MCM-56 was very active for liquid phase cumene synthesis from benzeneand C₃ ═. It provided a ˜45° C. temperature advantage over MCM-22 (65°C. vs. 110° C.) for stable operation at 300 psig, 3 benzene/C₃ ═molarratio, and 96% C₃ ═conversion (cf. FIG. 7). MCM-56 could be operated at20-30 C₃ ═WHSV with 90+% C₃ ═conversion (cf. FIG. 8). Table XIV comparesMCM-56's selectivity with MCM-22 and zeolite beta. In addition to itshigh activity for cumene synthesis, MCM-56 retained good productselectivity, comparable to MCM-22. Increasing C₃ ═WHSV from 2.5 to 10hr⁻¹ had little effect on MCM-56's product selectivity. Zeolite betaperformed poorly for cumene synthesis. Although initially active, itdeactivated rapidly due to C₃ ═oligomer formation. No deactivation wasobserved with MCM-56 during the four-week evaluation. Air regenerationdid not affect MCM-56 activity.

                  TABLE XIV                                                       ______________________________________                                        Cumene Synthesis from Benzene and C.sub.3 ═                               Catalyst/                Zeolite                                              35% Al.sub.2 O.sub.3                                                                          MCM-22   beta    MCM-56                                       ______________________________________                                        Temp, °C.                                                                              112      121     110   113                                    Days on stream  12.3     3.3     5.2   14.9                                   C.sub.3 ═ conversion, %                                                                   98.0     82.1    97.9  95.4                                   C.sub.3 ═ WHSV                                                                            1.3      2.5     2.5   10.0                                   Benzene WHSV    7        14      14    56                                     Benzene/C.sub.3 ═                                                                         3        3       3     3                                      molar ratio                                                                   Product selectivity, wt. %                                                    Cumene          84.85    84.25   84.52 84.98                                  Diisopropyl-    11.30    7.05    13.51 13.20                                  benzene (DiPB)                                                                Triisopropyl-   2.06     0.22    1.52  1.28                                   benzene+                                                                      Σ         98.21    91.52   99.55 99.46                                  C.sub.3 ═ oligomers                                                                       1.80     8.44    0.45  0.52                                   Aromatic lights 0.00     0.04    0.00  0.00                                   n-C.sub.3 -benzene                                                                            0.006    0.008   0.008 0.008                                  Σ (by-products)                                                                         1.81     9.49    0.46  0.53                                   DIPB/cumene,    0.133    0.084   0.160 0.127                                  wt/wt                                                                         n-C.sub.3 -benzene/                                                                           70       90      90    90                                     cumene, ppm                                                                   ______________________________________                                    

What is claimed is:
 1. A process for preparing short chain alkyl aromatic compounds, said process comprising contacting at least one alkylatable aromatic compound with at least one alkylating agent possessing an alkylating aliphatic group having from 1 to 5 carbon atoms under sufficient reaction conditions and in the presence of a catalyst to provide an alkylated aromatic product possessing at least one alkyl group derived from said alkylating agent, said catalyst comprising synthetic porous crystalline MCM-56.
 2. The process of claim 1 wherein the synthetic porous crystalline MCM-56 has a composition comprising the molar relationship

    X.sub.2 O.sub.3 :(n)YO.sub.2,

wherein n is less than about 35, X is a trivalent element and Y is a tetravalent element.
 3. The process of claim 2 wherein X is a trivalent element selected from the group consisting of aluminum, boron, iron, gallium, and mixtures thereof, and Y is a tetravalent element selected from the group consisting of silicon, titanium, germanium, and mixtures thereof.
 4. The process of claim 2 wherein n is from about 5 to about 25, and wherein said MCM-56 material has a sorption capacity for 1,3,5-trimethylbenzene of at least about 35 μl/gram of calcined synthetic material, an initial uptake of 15 mg of 2,2-dimethylbutane/gram of calcined synthetic material of less than about 20 seconds, and an X-ray diffraction pattern for the calcined synthetic material having d-spacing maxima at 12.4±0.2, 9.9±0.3, 6.9±0.1, 6.2±0.1, 3.55±0.07, and 3.42±0.07 Angstroms.
 5. The process of claim 4 wherein n is from about 10 to about
 20. 6. The process of claim 5 wherein X comprises aluminum and Y comprises silicon.
 7. The process of claim 1 wherein said synthetic porous crystalline MCM-56 has been treated to replace original cations, at least in part, with a cation or mixture of cations selected from the group consisting of hydrogen, hydrogen precursors, rare earth metals, and metals of Groups IIA, IIIA, IVA, IB, IIB, IIIB, IVB, VIB and VIII of the Periodic Table.
 8. The process of claim 7 wherein said synthetic porous crystalline MCM-56 has been thermally treated at a temperature up to about 925° C. in the presence or absence of steam.
 9. The process of claim 1 wherein said catalyst comprises a matrix material.
 10. The process of claim 9 wherein said matrix material comprises alumina, silica, zirconia, titania, or mixture thereof.
 11. The process of claim 10 wherein the catalyst is provided in the form of extrudate, beads or fluidizable microspheres.
 12. The process of claim 1 wherein benzene is alkylated with propylene under liquid phase conditions to produce cumene.
 13. The process of claim 1 wherein an alkylatable aromatic compound selected from the group consisting of benzene, xylene, toluene, and 1,2,3,5-tetramethylbenzene is alkylated with an olefin.
 14. The process of claim 1 wherein the alkylation reaction conditions include a temperature of from about 0° C. to about 500° C., a pressure of from about 0.2 to about 250 atmospheres, a WHSV of from about 0.1 to 500 hr⁻¹ and an alkylatable aromatic compound to alkylating agent mole ratio of from about 0.1:1 to 50:1.
 15. The process of claim 12 wherein the alkylation reaction conditions include a temperature of from about 10° C. to 125° C., a pressure of from about 1 to about 30 atmospheres, and a WHSV of from about 5 to about 50 hr⁻¹.
 16. The process of claim 12 wherein the alkylation reaction conditions include a temperature of from about 10° C. to 150° C., a pressure of from about 1 to about 30 atmospheres, and a WHSV of from about 5 to about 50 hr⁻¹.
 17. The process of claim 12 wherein the alkylation reaction conditions include a temperature of from about 10° C. to 250° C., a pressure of from about 1 to about 250 atmospheres, and a WHSV of from about 5 to about 250 hr⁻¹.
 18. The process of claim 1 wherein benzene is alkylated with ethylene under liquid phase conditions to produce ethylbenzene.
 19. The process of claim 18 wherein the alkylation reaction conditions include a temperature of from about 150° C. to 260° C., a pressure of 7000 kPa or less, a WHSV based on ethylene of from about 0.5 to about 2.0 hr⁻¹, and a mole ratio of benzene to ethylene of from 1:1 to 30:1. 